Flexible interbody implant

Abstract

A lumbar interbody fusion device includes a first wing, a second wing, and a bridge. The bridge has an arcuate resting shape and include a first end connected to the first wing, a second end connected to the second wing, and at least one aperture extending through the bridge in a radial direction relative to the arcuate resting shape of the bridge. The bridge is elastically deformable such that a distance between the first wing and the second wing may vary according to elastic deformation of the bridge.

The invention claimed is: 
     
       1. A lumbar interbody fusion device, comprising:
 a first wing and a second wing; and 
 a bridge monolithically formed with the first and second wing extending along a path from a first end connected to the first wing to a second end connected to the second wing, the bridge having at least one aperture extending through the bridge in a direction transverse to the path, the bridge being elastically deformable such that a distance between the first wing and the second wing may vary according to elastic deformation of the bridge. 
 
     
     
       2. The device of  claim 1 , wherein the first wing has a V shaped recess that is concave toward the second wing and the second wing has a V shaped projection that is convex toward the first wing, and wherein the V shaped projection extends into the V shaped recess when the bridge is in a resting shape. 
     
     
       3. The device of  claim 1 , wherein the bridge has an arcuate resting shape centered on an axis extending perpendicular to a radial direction of the arcuate resting shape, the axis extending from an inferior direction to a superior direction, and the wings being radially inward of the bridge in the radial direction. 
     
     
       4. The device of  claim 3 , wherein the at least one aperture is a plurality of slots extending across bridge from an inferior edge of the bridge and from a superior edge of the bridge to define a serpentine bar shape of the bridge. 
     
     
       5. The device of  claim 3 , wherein a cavity extends through the bridge between the first and the second end, and wherein the at least one aperture includes a spiral slot extending along the bridge between the first end and the second end, the spiral slot providing an opening from the cavity to an exterior surface of the bridge. 
     
     
       6. The device of  claim 5 , wherein the bridge is a coil shaped element extending from the first end to the second end. 
     
     
       7. The device of  claim 3 , wherein the path extends along a flexure plane, a width of the bridge is defined perpendicular to the flexure plane, and the width of the bridge is greater than a thickness of the bridge on the flexure plane at every location between the first end and the second end. 
     
     
       8. The device of  claim 7 , wherein flexure of the bridge perpendicular to its width corresponds to movement of the first wing and second wing along the flexure plane. 
     
     
       9. A method of manufacturing the fusion device of  claim 1 , comprising:
 additively manufacturing the device by stacking layers in an axial direction perpendicular to the path. 
 
     
     
       10. The method of  claim 9 , wherein the layers are layers of titanium. 
     
     
       11. A method of assembling an interbody device, the method including:
 positioning a first wing adjacent a second wing such that a fulcrum extending from the first wing extends along a lateral axis toward a socket provided by the second wing; 
 inserting the fulcrum into the socket by moving the first and second wings towards one another along the lateral axis; and 
 rotating the first wing relative to the second wing such that the fulcrum turns within the socket about the lateral axis. 
 
     
     
       12. The method of  claim 11 , wherein the fulcrum engages tabs partially enclosing the socket, thereby preventing withdrawal of the fulcrum from the socket along the fulcrum axis when the rotating step is completed. 
     
     
       13. The method of  claim 11 , wherein the rotating step is completed when a first channel extending through the first wing is aligned with a second channel extending through the second wing. 
     
     
       14. The method of  claim 13 , further comprising a step of inserting a leaf spring through the aligned first channel and second channel. 
     
     
       15. The method of  claim 11 , wherein the rotating step is completed when the first wing is rotated along the lateral axis into an orientation generally perpendicular to the second wing. 
     
     
       16. A lumbar interbody fusion device, comprising:
 a first wing and a second wing connected to one another in a first relative orientation; and 
 an elastic biasing element maintaining the first wing and the second wing in contact with one another at a pivoting contact point; 
 wherein, absent the biasing element, the first wing and the second wing would be freely separable from one another when the first and second wings are positioned in a second relative orientation with respect to one another. 
 
     
     
       17. The device of  claim 16 , wherein the elastic biasing element includes a first end bearing on the first wing and a second end bearing on the second wing and being oriented to bias the first wing relative to the second wing about the pivoting contact point toward a rest position. 
     
     
       18. The device of  claim 17 , wherein the biasing element is a coil spring or a leaf spring. 
     
     
       19. The device of  claim 16 , wherein the first wing includes a first outer facet and a first inner facet and is movable about the pivoting contact point between a first position in which the first outer facet bears on the second wing and a second position in which the first inner facet bears on the second wing. 
     
     
       20. The device of  claim 19 , wherein the first wing defines a vertex between the first inner facet and the first outer facet upon which the first wing rocks when rotating about the pivoting contact point.